A state-of-the-art review of distributed optical fiber sensor technologies has been carried out. The studied methods include polarization-modulation-based, Brillouin-scattering-based, and frequency-modulated continuous-wave (FMCW) methods as well as optical coherence domain reflectometry (OCDR) and interferometric distributed sensing techniques. A classification of the methods with their main properties for measuring quantity information continuously from a long sensor fiber is carried out. The main emphasis is on the comparison of the methods with respect to their spatial resolution, measurement time, and measurement range. The FMCW methods are found to be the most versatile techniques for various applications, due to their short measurement times with measurement ranges extending up to tens of kilometers and location sensing resolution better than 0.1%. The OCDR methods are fast and compete with the FMCW methods in versaility, especially when the measurement range is shorter than 1 to 2 km. © 2002 Society of Photo-Optical Instrumentation Engineers.